The invention relates generally to systems and methods for power generation, using oxy-fuel combustion. More particularly, the invention relates to gas-turbines that include plasma generators for enhanced flame stability.
Exhaust streams generated by the combustion of fossil fuels in, for example, power generation systems, contain nitrogen oxides (NOX) and carbon monoxide (CO) as byproducts during combustion. NOx and CO emissions from power plants utilizing fossil fuels are increasingly penalized by national and international regulations. With increasing costs for emitting NOx and CO, emission reduction is important for economic power generation.
One method of reducing NOx emissions is to remove NOx from the exhaust gas through selective catalytic reduction. A method for achieving near zero NOX, without the need for removal of NOx from the exhaust, is the oxy-fuel combustion process. In this method, pure oxygen (typically in combination with a secondary gas such as CO2) is used as the oxidizer, as opposed to using air, thereby resulting in a flue gas with negligible NOx emissions. In the oxy-fuel process, a lower exhaust CO emission can be produced when a combustion flame can be stabilized with the lowest possible O2 concentrations in the oxidizer. The minimized O2 oxidizer further results in lower O2 content in the exhaust stream. In addition, operating the combustion process close to a stoichiometric fuel-to-oxygen ratio (φ=1), or with a slightly richer fuel, minimizes the O2 content in the exhaust, enabling high CO2 concentrations for downstream processes. However, the reduction in oxy-fuel O2 concentration below a certain level may lead to flame stability issues.
Therefore, there is a need for a system and method for power generation that ensures lower levels of NOx and CO emissions, along with maintaining flame stability.